1. Field of the Invention
The present invention relates to semiconductor fabrication technology; and, more particularly, to a metal-insulator-metal (MIM) capacitor and a method for fabricating the same.
2. Description of Related Art
An MIM capacitor is used in an analog circuit and a radio frequency (RF) circuit. The MIM capacitor is used when a capacitor of a high quality factor Q having a low serial resistance is needed. Furthermore, the MIM capacitor is used on behalf of analog capacitors due to its low thermal budget and low power voltage and low parasitic capacitance.
FIGS. 1A to 1E are cross-sectional views illustrating a conventional method for fabricating an MIM capacitor.
As shown in FIG. 1A, a lower metal line 102 is formed on a substrate 101. A lower electrode 103, a dielectric layer 104 and an upper electrode 105 are sequentially formed on the lower metal line 102.
Referring to FIG. 1B, the upper electrode 105 is etched to form an upper electrode pattern 105A, and the dielectric layer 104 is also partially etched to form a first dielectric layer pattern 104A. Here, the first dielectric layer pattern 104A remains on the lower electrode 103 in a predetermined thickness.
Referring to FIG. 1C, the remaining first dielectric layer pattern 104A is etched to form a second dielectric layer pattern 104B.
Referring to FIG. 1D, the lower electrode 103 and the lower metal line 102 are sequentially etched to form a lower electrode pattern 103A and a lower metal line pattern 102A.
Referring to FIG. 1E, by performing a line process after forming an inter-layer insulation layer 106, first and second vias 107 and 108 are formed inside the inter-layer insulation layer 106, and an upper metal line 111 is formed thereon. The upper metal line 111 is a stack layer of first and second layers 109 and 110.
In the conventional method of fabricating the MIM capacitor, due to polymer or various kinds of conductive residues, the upper electrode pattern 105A is not electrically isolated from the lower electrode pattern 103A or the lower metal line pattern 102A which functions as a part of the lower electrode pattern 103A. As a result, they are shorted and thus a leakage current is generated.